fc-cache: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/fc-cache - from package: fontconfig

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/fc-cache - from package: fontconfig

You may install the required package with command apt-get install {package}

Error in other languages:
fc-cache: bevel nie gevind nie
fc-cache: comandă negăsită
fc-cache: comando não encontrado
fc-cache: commande introuvable
fc-cache: command not found
fc-cache: käsku ei ole
fc-cache: không tìm thấy lệnh
fc-cache: komanda nerasta
fc-cache: Kommando nicht gefunden.
fc-cache: kommandot finns inte
fc-cache: komut yok
fc-cache: nie znaleziono polecenia
fc-cache: níor aimsíodh an t-ordú
fc-cache: no se encontró la orden
fc-cache: no s'ha trobat l'ordre
fc-cache: opdracht niet gevonden
fc-cache: parancs nem található
fc-cache: perintah tidak ditemukan
fc-cache: príkaz nenájdený
fc-cache: příkaz nenalezen
fc-cache: команда не найдена
fc-cache: командата не е открита
fc-cache: 命令找不到
fc-cache: コマンドが見つかりません